A believe that’s called a reference point.
Explanation:
The Simple Pendulum. A simple pendulum is defined to have a point mass, also known as the pendulum bob, which is suspended from a string of length L with negligible mass ((Figure)). Here, the only forces acting on the bob are the force of gravity (i.e., the weight of the bob) and tension from the string.
hope it helps you
Answer:
according to this question best answer is C
Any process in which a mixture of materials separates out partially